RADIOTELEMETRICALLY RECORDED BLOOD-PRESSURE AND HEART-RATE CHANGES INRELATION TO PLASMA-CATECHOLAMINE LEVELS DURING PARTURITION IN THE CONSCIOUS, UNRESTRAINED GOAT

The aim of this study was to investigate the extent of sympathetic ner vous system activation during parturition in four unrestrained goats. Chronically implanted radiotelemetry devices registered heart rate and arterial blood pressure around the clock and blood was sampled for de termination of plasma adrenaline and noradrenaline concentrations befo re, during and after labour. Two goats delivered two kids after modera tely intensive abdominal contractions. A third goat had dystocia, and was treated with prostaglandin F-2 alpha One normal kid and one mummif ied foetus were delivered manually. After milking, a third kid was bor n spontaneously. The fourth goal experienced severe abdominal contract ions and delivered one kid. Mean blood pressure was 69 +/- 2 mmHg the day before parturition, increased gradually during the labour pains, a nd reached a maximal value of 120 +/- 7 mmHg when the head of the firs t kid was visible (P less than or equal to 0.05). Hear? rate was 134 /- 4 beats min(-1) the day before parturition and peaked when the firs t kid was born (159 +/- 6 beats min(-1), P less than or equal to 0.05) , as did plasma adrenaline concentration (from 0.4 +/- 0.2 nmol L-1 to 2.7 +/- 1.2 nmol L-1, P less than or equal to 0.05). The concentratio n of noradrenaline increased from 4.8 +/- 2.3 nmol L-1 to 12.2 +/- 8.4 nmol L-1 (P less than or equal to 0.05), when the head of the first k id was visible. Expulsion of the second and third kids caused relative ly smaller increases ir blood pressure, heart rats and catecholamines than those seen with the first born kid, it is concluded that changes in pressure, heart rate and catecholamines during parturition are rela ted to the different phases of labour and not to its duration or sever ity.